Vn N

Figure 9.11 The formation of two examples of the tetraponerines from ants. Glutamic acid, ornithine and y-aminobutyric acid uniformly labelled with 14 C, sodium acetate labelled in C-l and C-2 with 14C, and [ 1,4-14CJputrescine were all used to show the synthesis is as shown

Recently a whole series of indolizidine and pyrrolo-indolizidine alkaloids have been found in Myrmicaria ants (Figure 9.12), which evidently have a similar origin to the indolizidines in Figure 9.10. Note that they are all constructed from straight carbon chains. The structures of the complex dimer and trimer were deduced from NMR and mass spectral studies.

a pyrroioindolizidine v a pyrroioindolizidine v dimer dimer

trimer

Figure 9.12 Some complex alkaloids from the venom o/Myrmicaria ants from Africa.

Their biosynthesis has not been studied, but they can been viewed as producedfrom the diketopiperidine shown in the smaller structures in the lower part of thefigure